“It’s one thing I look forward to doing all year,” said Carroll, who has worked as a window washer for 15 years.

After rappelling down the side of the building, Carroll and Corcoran went inside to meet the kids, who were appropriately shocked to come face-to-face with their high-flying heroes.

“The first time it happened, I was kinda crying because it means a lot to those kids,” Carroll said.

Carroll and Corcoran work at ISS Facility Services, which washes windows for Mayo Clinic. Charlie Kleber worked with Mayo Clinic to set up the special event, and said he picked some of his best guys to swing down and make the kids smile.

He said he’s watched even the sickest kids come alive when they’re face-to-face with the superheroes.

He called Wednesday’s superhero experience “life-changing,” and said they were all struck by a special patient: 13-year-old Claire Strawman, who in April became the youngest heart-lung patient Mayo Clinic had ever transplanted.

She told them about how she went into lung failure and underwent a transplant in April. She was hospitalized for about seven months before being released a few weeks ago. But she got sick on Monday and needed to come back.

“I got goose bumps right now telling you that story,” Kleber said.

Claire is on immunosuppressant drugs to prevent her from rejecting the new organs, but the drugs also make her more prone to infections. When she got sick, her parents worried and brought her back to the hospital, according to her mom, Ellen Strawman. She was in the pediatric ICU when the superheroes visited.

“Just seeing them put a big smile on her face,” Strawman said, adding that Claire left the hospital today for her home in Bloomington, Minnesota.

“She told us what happened to her and everything. We were all standing around her tearing up,” Carroll said. “That story made you feel so proud to do it for the kids because it means so much to them. It was great.”

It’s been 10 years since Alyssa Dreiver’s twin sister died, but people still mistake her for Anissa.

They were identical, with blonde hair, brown eyes and matching smiles. When they spoke the same word at the same time, their throats would vibrate, Dreiver said.

But then a driver hit Anissa’s car head-on, killing her instantly when she was 25 years old.

Losing Their ‘Other Half’

“On February 1st 2004, my world was shattered,” Dreiver, now 35, told ABC News. “When I looked at her in the casket, I felt as if I was looking at myself.”

The two were inseparable growing up in Oklahoma, Dreiver said. They wore matching outfits, but in different colors. When Dreiver cut her hair during her senior year of high school, Anissa cried because they no longer looked exactly alike. Even after they moved to separate cities and got married, they would still drive six hours to see one another every few months and sleep in the same bed.

Courtesy Alyssa Driever

PHOTO: When Alyssa cut her hair in high school, Anissa cried because they no longer looked exactly the same.

Though Dreiver had experienced other close family members’ deaths, Anissa’s death was different, she said.

“Anissa is half of me. She is half of my soul. She’s a part of me. She’s my best friend. She’s like my shadow,” Dreiver said. “And I no longer have that.”

Dreiver said she has had a hard time coping. Every time she looks in the mirror, she remembers what she lost, she said.

Finding Twinless Twins

Last week, Dreiver found a Facebook support group for “twinless” twins – people who have lost their twin.

“I already feel a wonderful connection with them that I haven’t felt with any counselor or friend or anything like that,” she said. “No counselor I have ever been to can help me because they don’t understand.”

The national Twinless Twins Support Group has been around for decades, but the Facebook group has helped connect even more people over the last few years, especially those between 25 and 35 years old, said the group’s administrator, Dawn Barnett. Although there were 250 Twinless Twin Facebook group members in 2012, there are now nearly 1,500.

“We believe that by helping other twinless twins who are grieving, it helps you,” Barnett said, echoing Alyssa’s point about how other people don’t quite understand. “Twin loss is so deep because you were bonded from the womb on.”

Domenick Abbate, 40, who said he always felt like the big brother figure to his twin Frank, said the two of them were so close that they swore they could share dreams as children.

Courtesy Domenick Abbate

PHOTO: Domenick Abbate became depressed after his twin's death, but he recently discovered Twinless Twins, a support group that understands what he's going through.

Frank, a canine handler for the New Brunswick Fire Department following the September 11 attacks, died of lymphoma in 2010, Abbate said. He tried to keep moving forward, but eventually he started drinking, missing work and experiencing marital problems.

“The minute I got home, I wanted to crawl into a ball,” he said. “You still feel that missing connection. It was basically eating me up inside."

His wife was the one who found the twinless twins group and suggested he go to their annual conference in mid-July. He felt an almost immediate connection, he said. He loved how the group members would know when he needed a hug even before he did.

“We almost all had the same story in the end -- how we were feeling” he said. “No one else understood. My sister, my mother, they all say ‘I understand how you feel,’ but they didn’t.”

No Longer Living as ‘We’

Carolyn Landis, a psychologist at UH Rainbow Babies and Children’s Hospital in Cleveland, Ohio, said how someone handles the death of a twin can vary depending on a variety of factors, including how close the twins were and even how much they looked alike.

“Especially with identical twins, you would remind yourself of your twin,” Landis said. “It’s a similar phenomenon to a parent that loses a spouse and sees aspects of their spouse in their child.”

Landis said the surviving twin should focus on how he or she is unique as part of the healing process. Writing down memories in a journal can help, too.

But regardless of whether twins are identical, Landis notes that they went through every milestone -- from starting kindergarten to leaving for college to turning 30 -- together. Experiencing new milestones alone may be especially hard for the surviving twin, she said.

“Now you’re a single person, and you’ve been living as a ‘we,’” Barnett said. “You live a different normal.”

Landis said that technology from Skype to unlimited long distance calling can keep twins connected in a way that growing up might have pushed them apart in decades past. As a result, the death is painful even if twins didn’t live in the same city.

Landis said some surviving twins may fall into depression and should not be afraid to seek help from a therapist. Some survivors seek religion, too.

Early Twin Loss

But not all surviving twins remember the twin they lost. Dawn Barnett, who runs the Facebook group, said her identical twin died when the two were 10 months old in 1948. “All my life, I felt I wasn’t a twin because I didn’t get to live with her,” Barnett said. “My parents were in such grief. My parents never talked about her.”

But she came to embrace being a twin after seeing the Twinless Twins Support Group on a talk show in the mid-1980s and deciding to get involved.

Barnett felt especially close to her twin after having a heart attack in 2005. Her twin’s cause of death had been a heart problem in infancy nearly six decades earlier. Barnett spent several days in a coma and said her twin came to her and told her it wasn’t time to die yet.

Courtesy Dawn Barnett

PHOTO: Twinless Twins support group brings people whose twin has died together.

At the annual Twinless Twins conference this year, about 120 attendees – 10 percent of the total group – lost twins in utero or as babies, Barnett said, noting that the organization doesn’t keep statistics.

Kevin Mullen, 33, of Vermont, is among them. Mullen’s twin died when his umbilical cord wrapped around his neck and a blood clot formed, he said. Mullen himself was born with cerebral palsy. The only photo Mullen has of the two of them is an ultrasound photo.

“I’ve always been around twins. I have twin cousins, several sets of twin cousins,” he said. “Even though I do miss my twin, I honor him in different ways.”

Mullen happened upon Twinless Twins in the 1990s and said he honors his twin by participating in memorial walks and fundraisers for the group.

He said milestones, like turning 16 and going to Europe, always made him think of his twin because it would have been something they could share together.

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Courtesy Domenick Abbate

PHOTO: Twins Domenick and Frank Abbate grew up so close that they said they could share dreams. When Frank died, it was especially hard on Domenick.

Kendra Felder, 24, said she feels the same way. She found out about her twin sister when she was about 8 years old. Her twin, Courtney, died 11 days after they were born premature. On their birthday, she said she likes to find Courtney’s baby blanket and put it in a shadow box. She always thinks of her twin when a friend or family member dies and when she finds herself in a period of transition.

Landis said she’s had patients who don’t remember their twins but still think about them and talk to them.

“The fact that you were together in the womb, there’s something about that connection,” Landis said.

It’s important for parents to be transparent about the deceased twin by talking about it openly and making sure the surviving child doesn’t feel guilty, Landis added. The missing twin should never be a secret, and may even become a source of comfort.

Remembering Anissa

Driever talks about her twin sister, Anissa, every day even though she’s been dead for 10 years, she said. When she switched jobs, her coworkers said they felt like they were losing two people instead of just one because Driever talked about Anissa so much that she became alive for them.

“I love whenever somebody mistakes me for Anissa,” she said. “It warms my heart because I don’t want my sister to be forgotten. I talk about her or I think about her every day.”

Courtesy Alyssa Driever

PHOTO: Alyssa Driever's twin sister Anissa died nearly a decade ago, but the loss still hurts, she said.

For all the impressive advancements in medical technology, researchers and scientists still face a daunting challenge when they study the habits of the adorable but uncommunicative subjects called human infants.

In order to study infants without overwhelming them, scientists often try to mask the massive machines needed to view brain activity either by having the child sleep through it or by covering it in kid-friendly decorations. Other researchers have devised decidedly low-tech ways of reading an infant’s interest in a subject, even when they can’t say a single word.

In a study released Monday in the Proceedings of National Academy of Sciences, doctors used a special machine to examine infant brain activity as they start to learn language skills.

Patricia Kuhl, a professor of speech and hearing sciences at University of Washington and the lead author of the study, said the research indicated the area of the infants’ brain that controlled motor skills lit up when they heard certain words. The activity indicated that the infants are trying to mimic adults and speak much earlier before they say their first word.

However, Kuhl said, the study was important because of both the surprising findings and the way researchers were able to get them. To “read” the infant’s brain activity, they used the cutting-edge device called a magnetoencephalograph, that was quiet and nimble enough to read the chaotic world of infants’ brain activity.

Kuhl said unlike an MRI machine, which is extremely loud and requires a patient to be totally still, the magnetoencephalograph is nearly silent. However the infants still had to be strapped into a chair, so to keep them entertained the researchers were tasked with making silly faces and holding up toys all in the name of science.

“You want them to like the lab,” said Kuhl. “It’s decorated with fish and it’s got little stickies [on it.] It’s ... very baby friendly. We wave toys and we’re very aware and of their curiosity and of their desire to play. We do everything to make them comfortable.”

In a 2013 study published in Psychological Science, researchers used MRI machines to examine baby’s brain activity in response to different stimuli. However, to get the infants into a machine where they could not move, the researchers had the babies go in after they fell asleep naturally. They also used ear coverings so the loud MRI machine didn’t wake the infants.

MRI machines can be so distressing for patients because of claustrophobia or other fears about being in the hospital that a New York Hospital installed a pirate-themed scanner to put children (and some parents) more at ease.

“The genius is in this machine. ... There’s no noise and the baby can listen and can move,” said Kuhl of the magnetoencephalograph. “The ability for the first time to do this kind of recording in this kind of technical advanced machine ... [it’s like] we’re putting [on] a stethoscope.”

Fei Xue, a professor of psychology at the University of California Berkeley, has done numerous studies examining how infants learn and react to new toys or information. She said researchers have plenty of tricks to keep babies focused on the tasks at hand.

By now you’ve probably heard thatobesity increases the risk of heart disease and diabetes. But you might not know that the extra weight can have other serious health consequences, including cancer.

A new study found that 10 percent of all gallbladder, kidney, liver, and colon cancers could be attributed to excess weight. A whopping 41 percent of uterine cancers were tied to obesity, according to the study published today in The Lancet.

The Lancet study of 5.4 million people found that every 1-point population-wide increase in body mass index or BMI would result in 3,790 additional cancers each year. That’s worrying, considering that the average BMI in the U.S. has risen nearly 2.5 points for men and almost four points for women since 1971, according to a 2013 study.

The National Cancer Institute estimates that obesity contributes to 34,000 new cases of cancer in men and 50,000 in women each year. But if every adult reduced their BMI by 1 percent – a loss of roughly 2.2 pounds – about 100,000 new cases of cancer could be avoided, according to the agency’s website.

Migraines

A study published in the journal Neurology revealed what a real headache carrying extra weight can be.

Johns Hopkins researchers surveyed nearly 4,000 people to find that the higher their body mass index, the greater their chances were of having episodic migraines. Those who were obese were 81 percent more likely to experience at least 14 migraine headaches each month compared to people who were a healthy weight. Obese women over the age of 50 suffered from chronic headaches the most.

Infertility

Overweight women have a harder time getting pregnant. One Indian study of 300 morbidly obese women found that over 90 percent of them developed polycystic ovarian disease, a condition associated with infertility, over a three-year period.

As with cancer, the association between obesity and infertility isn't entirely clear.

"Obesity is an inflammatory state and that alone might decrease fertility," noted Dr. Marc Bessler, director of the Center for Weight Loss and Metabolic Surgery at New York Presbyterian Hospital at Columbia University Medical Center. "It may also be the result of hormone changes produced by the fatty tissue."

Bessler said that many of his heavier patients experienced difficulty getting pregnant. And many infertility clinics don't accept female patients with high body mass indexes given their diminished chances of conceiving. However, Bessler said some of his patients become pregnant just months after weight-loss surgery once they had dropped a few pounds.

Premature Birth

For heavier women who do get pregnant, the worries aren't over. A study in the Journal of the American Medical Association found that obesity increases a woman's chance of having a pre-term baby, especially when her body mass index is 35 or higher.

The study's authors speculate that having too much fat may inflame and weaken the uterine and cervical membranes. Whatever the reason, it can have devastating effects. Premature birth is the leading cause of infant death and long-term disabilities.

Sleep Disorders

Sleep and excess weight do not make good bedfellows. Nearly 80 percent of older, obese Americans report having problems with sleep, an American Sleep Foundation survey found.

Poor sleep contributes to a host of diseases including diabetes, heart disease and, ironically, obesity itself. Numerous studies link short sleep to expanding waistlines, including the Harvard Nurses' Study, which found that those who slumbered less than five hours a night were 15 percent more likely to gain weight than those who enjoyed at least seven hours of sleep.

Dr. Donald Hensrud, a nutritionist and preventive medicine expert in the department of endocrinology, diabetes, metabolism and nutrition at the Mayo Clinic, said one of the most immediate health dangers for many obese people is sleep apnea, a condition in which a person gasps or stops breathing momentarily while asleep.

"Sleep apnea can be caused by increased fat around the neck area that presses down and closes off the soft tissues of the airways while a person is lying down, especially on his back," Hensrud said. "This means the person does not get good quality sleep, has less oxygen in the blood stream, and the heart has to work harder."

Bullying

Though fat people are often the butt of the joke, obesity stigma is no laughing matter.

A Yale study found that weight is the number one reason people are bullied at any age and those who are bullied have lower self-esteem, higher levels of depression and increased risk of suicide.

The main source of ridicule, according to the Yale researchers: Loved ones.

Difficulty Finding Doctors

The number two source of stigma, after loved ones?

Puhl said her studies have found that 67 percent of overweight men and women report being shamed or bullied in the doctor's office. And 50 percent of doctors found that fat patients were "awkward, ugly, weak-willed and unlikely to comply with treatment" while 24 percent of nurses said they were repulsed by their obese patients.

Smaller Wages

Wider waistbands seem to widen the pay gap.

One George Washington University School of Public Health study found a strong connection between greater obesity and shrinking wages. Examining data from the 2004 National Longitudinal Survey of Youth, the researchers discovered that wages among the obese were $8,666 less for females and $4,772 lower for males compared with their thinner counterparts. In 2008, the researchers found wages were $5,826 less for obese females -- a 14.6 percent penalty over normal-weight females.

The worst-ever outbreak of Legionnaires’ disease in New York City has yet to be stopped as health officials today raised the total number of dead to 10 with 100 people infected.

Those who died were older adults with underlying medical conditions, according to city health officials.

Mayor Bill de Blasio said earlier this week that officials had expected cases to wane in upcoming days to weeks, but an increased number of cases have highlighted how difficult it can be to stop a Legionnaires’ outbreak.

The bacterial disease is spread when contaminated water-mist is inhaled. It can be spread through fountains, shower heads or air conditioning cooling units that mist water from the machinery. The New York City Health Department said it has found and tested 17 cooling towers in the area where the outbreak occurred and five tested positive for the bacteria.

Officials have already cleaned and flushed those cooling towers, but they are continuing to investigate whether there are any other potential sources for infection. De Blasio said this outbreak prompted him to introduce new legislation to cut down on future outbreaks.

In a news conference, he said the legislation would require new inspection standards for buildings with cooling and condensing units. If the bacteria is detected in the units, the building managers will be immediately required to take action or face penalties. If building managers fail to act, the city will step in.

Dr. William Schaffner, an infectious disease expert from Vanderbilt University Medical Center in Nashville, Tennessee, said stopping such outbreaks could be difficult because the Legionella bacteria that causes Legionnaires’ disease is naturally occurring in the environment.

"First of all, Legionnaires’ disease is not a predictable event; it occurs here, there and everywhere," Schaffner said. "Very few [outbreaks] are this large."

The source of the outbreak can also be hard to identify, Schaffner said, because of the difficulty of connecting bacteria found in cooling towers to the people affected by the disease.

ABC News' chief health and medical editor, Dr. Richard Besser, said he was concerned about statements made by city health officials saying they were confident that one or more of the five cooling towers was the source of the outbreak.

"Outbreaks of Legionnaires’ disease can be very difficult to sort out. Most people who are exposed don't get sick and the bacteria can travel in mist through the air over large distances," Besser said. "They [health officials] say they are confident that one or more of those cooling towers is the source.

"However, I think it's pretty hard to be certain without matching bacteria from the cooling tower to a patient -- something that has not been possible, or seeing that the number of cases declines. Without that decline, it seems a bit premature to be confident that this is over."

Schaffner said the next few days to weeks will be key to determining whether the source of the outbreak had been stopped or whether people are still presenting with new cases.

"It could [take] time for a diagnosis to be made and information to be reported to health department," Schaffner said. "We’d hope that cases clearly diminish in next week or two."

A second person has died of the plague this summer in Colorado and health officials are warning residents to take steps to guard against contracting the bacterial disease as the weather creates an opportunity for more cases to develop.

Officials from the Pueblo City Council Health Department announced this week the unnamed patient died from to a suspected case of septicemic plague, which leads to a dangerous blood infection. About seven people are diagnosed with a form of the plague in the United States every year, according to the U.S. Centers for Disease Control and Prevention.

Dr. Chris Nevin-Woods, medical officer at the Pueblo City Council Health Department, said they've recently seen a rise in zoonotic diseases, or diseases spread by bugs or animals in the area.

"We’re seeing a lot of zoonotic diseases but plague is relatively rare," she said. "Each case is very worrisome."

The disease is caused by the Yersinia pestis bacteria and will incubate in a person between two to six days before they show symptoms. There are three kinds of plague: bubonic, which leads to swollen lymph nodes; septicemic, which leads to a blood infection; and pneumatic, which is when the bacteria settle in the blood and cause pneumonia.

Nevin-Woods explained that prairie dogs can become infected with fleas that carry the virus and, eventually, those fleas can spread the disease to other animals or even people in the area.

"They’re everywhere and they have lots of fleas this year [because] we have a cool and very wet summer," she explained.

She said health officials are warning residents not to let their dogs or cats roam outside because the animals can pick up the infected fleas and bring them in the house. Dogs can be especially problematic because they can be asymptomatic and owners can have no idea the fleas they bring back are infected.

Dr. Frank Esper, infectious disease specialist at University Hospitals Case Medical Center in Cleveland, said about 80 percent of plague cases are bubonic, which is also the least dangerous form of the disease with death from it extremely rare in the United States.

"The amount of human infections is quite low," Esper said. "That’s not to say that plague itself is eradicated. It follows infections from rodents with the fleas," to pets in the home.

He explained in rare cases a bite from an infected flea will lead to an infection in the blood stream rather than in the lymph nodes. In that case, the septicemia form of the disease can occur, which can cause heart and lung failure as the immune system responds to the bacteria in the blood.

"If it goes to an artery or vein … It gets into the heart and spreads to other places of the body," he said. "Thankfully, it doesn’t happen very often."

Esper said the disease can be treated with antibiotics but that the septicemic form of the disease can work quickly. A vaccine for the disease exists and is given to those who are likely to come in close contact with the disease, such as scientists in a lab or animal-control workers.